The present invention relates generally to a zoom lens and an imaging system incorporating it, and more particularly to a high-zoom-ratio zoom lens lending itself to an electronic image pickup device such as a CCD or C-MOS and an imaging system incorporating it.
Zoom lens systems having a high zoom ratio, good image-formation capability and a short total length, which comprise, in order from the object side, a positive first lens group, a negative second lens group, a positive third lens group and a fourth lens group wherein all the lens groups are operable to move for zooming, are set forth typically in patent publications 1, 2 and 3.
Patent Publication 1
U.S. Pat. No. 3,008,380
Patent Publication 2
JP(A)7-5361
Patent Publication 3
JP(A)2004-12639